A regional community has met for a vigil for three young siblings killed in a shed fire in southwest Victoria.
Four children were playing together in the rear shed of a Corio property near Geelong on Sunday morning when it caught alight.
Three-year-old Saige McGregor and 18-month-old Ashlynn McGregor died at the scene.
Their six-year-old sister and four-year-old brother Isaac McGregor were flown to the Royal Children's Hospital in a critical condition.
Victoria Police confirmed Isaac died in hospital on Wednesday.
Members of the family's local community gathered on Saturday evening to pay their respects and show support at a vigil at Rosewall Reserve in Corio.
"The family needs all the support they can have," organiser Torii Janine Sanderson told AAP.
"As a community, we should all stand together and do what we can to help."
Mourners brought flowers, battery-operated candles, teddy bears and balloons in remembrance of the children.
